Precipitated silica

About: Precipitated silica is a research topic. Over the lifetime, 1401 publications have been published within this topic receiving 20992 citations.

Silica-filled rubber composition containing two different carbon blacks and tire produced by using the composition

Abstract: PROBLEM TO BE SOLVED: To provide a silica-filled rubber composition containing two different carbon blacks and a tire having a tread produced therefrom. SOLUTION: This rubber composition contains about 100 pts.wt. elastomer based on at least one diene, about 30-120phr particulate fillers comprising silica and carbon blacks (wherein the fillers contain about 15-60phr precipitated silica and about 15-60phr particulate carbon blacks comprising a mixture of a first carbon black having a DBP absorption of about 60-160cc/100g and an iodine value of about 25-85g/kg with a second carbon black having a DBP absorption of about 90-160cc/100g and an iodine value of about 90-150g/kg) and a silane coupling agent having both a part reactive with the surface of silica and a part interactive with an elastomer having a carbon-carbon double bond [the weight ratio of the coupling agent to the precipitated silica being (1:2) to (1:10)].

Sand mould casting release agent prepared through precipitated silica

Abstract: The invention discloses a sand mould casting release agent prepared through precipitated silica, and relates to the technical field of precipitated silica. The sand mould casting release agent is prepared from 15-20 parts of precipitated silica, 15-20 parts of cycloaliphatic epoxide resin, 15-20 parts of melamine resin, 8-12 parts of cinerite, 5-9 parts of petroleum coke, 4-7 parts of nitrocotton, 4-7 parts of hydrogenated castor oil, 3-6 parts of asbestos wool, 3-6 parts of sulphate aluminium cement, 2-4 parts of polyacrylamide, 2-4 parts of superfine glass dust, 2-4 parts of vulcanized lard oil, 1-2 parts of nanometer titanium dioxide, 1-2 parts of nanometer rubber powder, 1-2 parts of nano-graphite powder, 0.5-1 part of aluminum powder, 0.5-1 part of rice chaff ash, 20-25 parts of n-butyl acetate and 20-25 parts of n-butyl alcohol. The release agent is directly sprayed to a sand mould, a layer of isolating membrane can be formed on the surface of the sand mould, and therefore the release effect is achieved; and in addition, the isolating membrane is high in adherence and good in high-temperature resistance and abrasive resistance, and melting and gasification can be avoided in the casting process of castings.

A method for preparing a set accelerator, the product obtained and its use

Abstract: A method of preparing an alkali-free setting accelerator product for pulverized cement mixtures, such that starting from a mixture of: - a highly concentrated aluminum sulfate solution or suspension, between 8.2% and 21 % of Al2O3, prepared from aluminum sulfate in an aqueous solution with a concentration of between 1% and 12% in Al2O3 and / or aluminum sulfate in solid form with a concentration of between 14 and 27% of Al2O3 and at a temperature between 1 and 90 oC, and; - an amorphous aluminum hydroxycarbonate powder gel in a percentage between 0.1 and 15%, and / or; - an amine or alkanolamine, in particular a diethanolamine in a percentage between 0.1 and 8%, this starting mixture being prepared under continuous agitation, - performing a first stage where a synthetic silica derivative in a percentage between 0.1 and 10%, selected from the group of synthetic aluminum silicates, synthetic aluminum and sodium silicates, both crystalline and amorphous, amorphous precipitated silica and colloidal silica in aqueous solution is mixed with the stirring starting mixture; - performing a second stirring reaction stage in an aqueous medium at a temperature between 1 and 90 ° C for a period between 15 and 120 minutes, and; - performing a third stage of maturation at a temperature between 2 and 30 ° C with strong agitation for a period between 1 and 48 hours, obtaining a liquid solution of a setting accelerator.

The properties of ethylene–propylene elastomers obtained with the use of a new cross-linking substance

Abstract: In this work, the effect of a new filler on cross-linking of ethylene–propylene rubber (EPM) was investigated. A filler with a core–shell structure ZnO/SiO2 (precipitated silica modified with zinc oxide) was introduced into rubber compounds. It was proved using of those substance to cross-link EPM caused the formation of labile ionic clusters in elastomer network. These non-covalent cross-links were generated due to interactions occurring between metal ions and functional groups of rubber (namely carboxyl groups) introduced via rubber functionalization with maleic and itaconic acids derivatives. The optimal curing time of rubber compounds was investigated. The cross-link density of the vulcanizates obtained was studied by equilibrium swelling in solvents (e.g., toluene). Additionally, the results confirmed that vulcanizates received using modified silica contained specific cross-links disintegrating under ammonia vapors. Physical relaxation at ambient temperature confirmed the influence of non-covalent cross-links on stress dissipation in the vulcanizate. The static and dynamic mechanical properties of vulcanizates obtained were also determined.

High electrolyte additions for precipitated silica material production

Abstract: Precipitated silica comprising porous silica particles having a cumulative surface area for all pores having diameters greater than 500 A of less than 6 m2/g, as measured by mercury intrusion, and a percentage cetylpyridinium chloride (% CPC) Compatibility of greater than about 85%. The precipitated silica product is especially well-adapted for use in dentifrices containing cetylpyridinium chloride, which do not attach to the low surface area silica product in a meaningful level and thus remain available for antimicrobial action. Processes for making the silica product including the introduction of sodium sulfate powder during different process steps in order to enhance such a compatibility with CPC are provided.